wemay
Site Donor 2023
Engine Explosion Blows Truck Apart || ViralHog:
Cummins (modified) blows up on dyno @2:45
- Thread starter wemay
- Start date
Well...they successfully found the stress limit of that engine.
If only..
Quantum Blue
Quantum Blue
Jake from State Farm ain't gonna cover that.
Yes you are right. He was deliberately pushing the engine way beyond its limit.
Wow, seen videos of engines popping on a dyno before, but never that dramatic.
Yeah, coughs like that under load are never a good sign.
What ultimately happened was called a diesel runaway: https://en.wikipedia.org/wiki/Diesel_engine_runaway
Diesel engines don't have a throttle valve controlling air entering the engine. They are effectively always gulping in as much air as volumetric efficiency will allow them. The only thing that controls engine speed is engine fueling. More fuel, engine speeds up; less fuel, engine slows down.
With a runaway, there is an uncontrolled fuel source entering the engine. In modern diesels, this is typically oil introduced into the intake tract when a seal in the turbocharger lets go.
You can see that happen at 2:50. Puff of black smoke, extreme engine acceleration with a significant change in the color of the exhaust, then bang. The puff of black was the initial introduction of "other" fuel, the intense acceleration was all the unmetered fuel (oil), the change is color of the exhaust is because the engine is significantly leaning out, and the bang was when the insides see the outside.
I've never understood these types of videos; it is like building a craftsman house and instead of the enjoyment of living in it, you set it on fire to see if it will burn
wemay
Site Donor 2023
@MrHorspwer - thanks for the explanation.
Another great moment in sports brought to you by the "Hold My Beer" channel.
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They really should have chosen this for the soundtrack of the video...
I don't think it was runaway. It was just one of those engines doing what they do. The stuff they do to those engines borders on insane. Solid billet blocks, massive turbo pressures and massive amounts of fuel. They essentially have to light them off in stages or the engine will choke out. Not uncommon to see them melting down a set of brake pads in the rear to put enough load on the engine to get enough exhaust pressure to spool the massive turbos. Its all a bit crazy. Not something I would want to do, but makes for entertaining videos.
3000+ HP is usually the target they shoot for....and lots of them grenade.
" We had just crossed 2200HP at 146psi when the 6.7L Cummins block simply couldn't handle the pressure and separated! We have done over 3000HP on this longblock setup so we feel like it was definitely a premature failure, but we see no signs of a problem in the datalog, pistons or rods before the block split. It looks as though the failure was simply stress fatigue to the OEM Cummins Block. The Longblock had been Modified by D&J Precision Machine with a Deckplate, 1" longer rods, ductile Iron Sleeves and 9/16" head studs, main studs and custom girdle, all which held up to the abuse had the block not failed. D&J has a new billet block in production stages that will hopefully prove to increase block strength significantly. "
3000+ HP is usually the target they shoot for....and lots of them grenade.
" We had just crossed 2200HP at 146psi when the 6.7L Cummins block simply couldn't handle the pressure and separated! We have done over 3000HP on this longblock setup so we feel like it was definitely a premature failure, but we see no signs of a problem in the datalog, pistons or rods before the block split. It looks as though the failure was simply stress fatigue to the OEM Cummins Block. The Longblock had been Modified by D&J Precision Machine with a Deckplate, 1" longer rods, ductile Iron Sleeves and 9/16" head studs, main studs and custom girdle, all which held up to the abuse had the block not failed. D&J has a new billet block in production stages that will hopefully prove to increase block strength significantly. "
Yes sir you are exactly right. The only way to stop it is to cut the air intake off. When I was into generator services the big units always had a steel plate next to the intake so you could cut off the air supply in the event of a runaway motor.
I'm not convinced that was a runaway event. It seems to me that's just when he applied max power to start the run. If you watch the two dyno sequences side by side they look similar with the exception that one ends with a bang. Something let go in the engine is my un-expert opinion.
